"Dark Knight Rises" shooting: Suspect's home and belongings key to investigation

(CBS News) The gunman who opened fire at a midnight showing of the "The Dark Knight Rises" likely planned in advance, and suspect James Holmes' home and belongings will be key to the investigation, CBS News senior correspondent John Miller explained on "CBS This Morning."

"The information speaks," Miller said. "What you see here is, you see indications of an awful lot of...preparation and research that went into this."

Miller, a former assistant director at the FBI, noted the use of the dispersal device, used to spread gas or smoke, is particularly telling. Miller said the suspect likely used it to either allow him to hide and keep firing or fill the theater with smoke in order to drive people toward the exits to continue more targeting firing.

"Clearly, this is something that this individual didn't think up yesterday," Miller said. "It's not a spur-of-the-moment caper."

At least 12 people were killed and at least 50 injured inside the theater in Aurora, Colo.

Describing aerial pictures of authorities surrounding the suspect's apartment, Miller said, "You see a SWAT truck in the back. ... You can see an officer standing on the back of it, holding something on a pole. ... You have a tactical response to execute a search warrant.."

"The normal way to do that is, you either take the keys off the suspect and you go in, or you boom the door," Miller said. "They've got the back covered, and they're using a pole camera with fiber-optics to look through the windows. Because they are very concerned of if you have explosives there and you have a suspect who said 'here's my address, go to my house. Search my place,' There well could be booby traps that could be set up for the entry team."

Authorities will likely learn more following a search of the suspect's home and belongings, particularly if computers and hard drives are found, Miller said.

Miller said the shooter likely wanted his story to be told. "He certainly was caught and he was caught because he intended to be caught," Miller said. "He had ample opportunity to go away. He literally had a smoke screen to disappear into and he chose to be in the parking lot in the police response when he was captured. At least that's the information we see now. That tells us something, which is he didn't want to kill himself. And he probably wants his story to be told."

The suburb of Aurora, about 10 miles outside of Denver, is not a stranger to this kind of tragedy, Miller said. The Aurora area is in Arapahoe County, near Littleton, Colo., the site of the Columbine shootings in 1999 and where New York City subway plotter Najibullah Zazi had lived. The chief of police in Aurora, Daniel J. Oates, a former New York Police Department officer who retired at the rank of deputy chief, Miller said

"This is a community that has already been through and lived through a similar trauma like this within this generation," Miller said. "... For a suburban environment, they're kind of experienced in this kind of trauma if anyplace can be."